Lateral Semicircular Canal Asymmetry in Idiopathic Scoliosis: An Early Link between Biomechanical, Hormonal and Neurosensory Theories?

• Published in: PloS one Vol. 10; no. 7; p. e0131120
• Main Authors: Hitier, Martin, Hamon, Michèle, Denise, Pierre, Lacoudre, Julien, Thenint, Marie-Aude, Mallet, Jean-François, Moreau, Sylvain, Quarck, Gaëlle
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 17-07-2015; Public Library of Science (PLoS)
• Subjects: Abnormalities; Adolescent; Adolescents; Anomalies; Asymmetry; Biomechanical Phenomena; Biomechanics; Bone density; Brain research; Case-Control Studies; Cerebellum; Cerebellum - pathology; Cerebellum - physiopathology; Children; Cognitive science; Deformation mechanisms; Early Diagnosis; Endocrinology and metabolism; Engineering Sciences; Excitability; Family medical history; Female; Human health and pathology; Humans; Hypothalamus; Hypothalamus - pathology; Hypothalamus - physiopathology; Life Sciences; Magnetic Resonance Imaging; Male; Mechanics; Morbidity; Nervous system; Neuroscience; Orientation; Otolaryngology; Paresis; Pathogenesis; Pediatrics; Physical Stimulation; Prospective Studies; Rhumatology and musculoskeletal system; Scoliosis; Scoliosis - diagnosis; Scoliosis - pathology; Scoliosis - physiopathology; Semicircular Canals - pathology; Semicircular Canals - physiopathology; Sensory Receptor Cells - pathology; Spine - pathology; Spine - physiopathology; Surgery; Teenagers; Temperature; Vestibular system; Vestibule, Labyrinth - pathology; Vestibule, Labyrinth - physiopathology; Cerebellum; Semicircular canals; Magnetic resonance imaging; Spine; Pathogenesis; Bone remodeling; Hormones; Adolescents
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0131120

Despite its high incidence and severe morbidity, the physiopathogenesis of adolescent idiopathic scoliosis (AIS) is still unknown. Here, we looked for early anomalies in AIS which are likely to be the cause of spinal deformity and could also be targeted by early treatments. We focused on the vestibular system, which is suspected of acting in AIS pathogenesis and which exhibits an end organ with size and shape fixed before birth. We hypothesize that, in adolescents with idiopathic scoliosis, vestibular morphological anomalies were already present at birth and could possibly have caused other abnormalities.
The vestibular organ of 18 adolescents with AIS and 9 controls were evaluated with MRI in a prospective case controlled study. We studied lateral semicircular canal orientation and the three semicircular canal positions relative to the midline. Lateral semicircular canal function was also evaluated by vestibulonystagmography after bithermal caloric stimulation.
The left lateral semicircular canal was more vertical and further from the midline in AIS (p = 0.01) and these two parameters were highly correlated (r = -0.6; p = 0.02). These morphological anomalies were associated with functional anomalies in AIS (lower excitability, higher canal paresis), but were not significantly different from controls (p>0.05).
Adolescents with idiopathic scoliosis exhibit morphological vestibular asymmetry, probably determined well before birth. Since the vestibular system influences the vestibulospinal pathway, the hypothalamus, and the cerebellum, this indicates that the vestibular system is a possible cause of later morphological, hormonal and neurosensory anomalies observed in AIS. Moreover, the simple lateral SCC MRI measurement demonstrated here could be used for early detection of AIS, selection of children for close follow-up, and initiation of preventive treatment before spinal deformity occurs.